asp.net c# reflection, creating more instance then expected

I have a helper method here in class. It returns all the instances of a given interface in all the ap开发者_开发技巧p domain dlls.

public static class Helper
{
  public static List<T> GetOfType<T> ()
  {
    var t =  from asm in AppDomain.CurrentDomain.GetAssemblies()
                  from type in asm.GetTypes()
                  where !type.IsInterface && !type.IsAbstract && typeof(T).IsAssignableFrom(type)
                  select (T)Activator.CreateInstance(type);
   return t.List();
 }
}

Edit

Now say i have interface

IUserContent
{
  string URL {get;set;}

 }

and a implementation say PhotoContent

public class PhotoContent
{
     public string URL {get;set]}
}

now when i say

var c = Helper.GetOfType<IUserContent>();

It gives me 9 instances of IUserContent all pointing to photocontent

That is the problem. I couldnt understand what is the reason.

Can someone help here.

Regards Parminder

---

The first thing to do is to get the full name:

foreach(var obj in c) {
    Console.WriteLine(c.GetType().AssemblyQualifiedName);
}

that gives you the full type-names (including assemblies) of the types invovled. My guess would be that the type has been accidentally declared in multiple assembles or namespaces.

---

You have two from clauses in your LINQ query. Could it be that this causes the results to be returned multiple times? I would try using SelectMany instead:

var t = AppDomain.CurrentDomain.GetAssemblies()
    .SelectMany(a => a.GetTypes())
    .Where(type => !type.IsInterface && !type.IsAbstract && typeof(T).IsAssignableFrom(type))
    .Select(type => (T)Activator.CreateInstance(type));